Test-block for electric meters



Feb. 11, 1936. E. G. JOI-I-IANSSON 2,030,522

TEST BLOCK FOR ELECTRIC METERS Filed March 30, 1933 Patented Feb. 11, 19 136 ras'r-nnocx i on morale m'rnas Ernest G. Johansson, Watertown. Mala, assigncr to The Palmer Electric & Manufacturing 00., Waltham, Mara, a corporation of Massachulettc Application ma :0, 193:, Serial No. 663,523

16 Claims. (01. 175-103) This invention relates to a test-block adapted to facilitate the testing of an electric meter by compact and eflicient form, and can be employed.

without the use of tools.

According to the invention the block consists 15 of a base of insulating materialon which are mounted a suitable number of pairs of housing.

contact elements, each element being preferably of bar stock bent to shape to receive a plug between it and its opposing element, the bends being 20 such as to cause the contact portions of opposing elements to move closer to each other when heated, thus making a better interfacial connection with a plug between them. In each pair of contact elements, the contact portion of at least one 25 is formed to a non-flat shape, theplug having a corresponding shape to fit, so that the plug is held in an upright position when inserted between opposing elements.

An object of the invention is to provide a test- 30 block of which the structure is as compact as possible, consistent with the standard require-,-

ments of spacing between members of different polarity. As the spacing rules apply to movable as well as to fixed members, the movable 35 members are constructed and arranged so as to avoid any, position of operation in which they would be nearer to a member of different polarity than the minimum prescribed distance.

It a plug ispulled when it is carrying a load 40 current, arcing occurs, especially when a heavy current is being carried. To minimize such aremg, I may provide a barrier or insulating wall between the elements of each pair, such wall being preferably secured to the insulating base. This 45 prevents the jumping of an are from one element to the other when a plug is pulled. Any suitable insulating material such as vulcanized flber or the like may be used for the wall. Forked plugs are provided to straddle the wall, the legs of the 50 plugs engaging the opposing elements of a pair so as to connect them electrically. In addition to the wall or barrier between elements of each pair, I also provide adequate insulating barriers between contact elements of different voltages.

55 Thus the block can be compactly constructed so as to be enclosed in a box of comparatively small For a more complete disclosure of the invention, reference may be had to the description thereof which follows and to the drawing of which Figure 1 is a plan view of a box containing an electric meter and a test-block embodying the invention.

'Figure2isasectionon1ine2.2ofFigui-e1.

.Figureaisasectionon linel-iof Figure l.

Figure4isaperspective viewofapairofcontact elements, a fragment of the barrier between them, and a plug adapted to connect them.

Figure 5 is a sectional view of a pair of contact elements, the barrier between them, and a plug connecting them.

Figure 6is a section on line 6-8 of Figure 5.

Figure 7 is a similar section showing elements of different shape.

As indicated in Figure 1, the invention may be embodied in a block I l mountedin a box I I which is illustrated withoutthe usual cover. A meter I2 is also mounted in the box near the block II to as to be conveniently connected thereto by suitable conductors l8, l6, VI! and It. As shown, the block II is provided with ten contact elements designated as 2| II, 22, 23 24, II, 26, 21, 2| and 28. These elements are arranged in pairs, the elements of each pair being connectible by a suitable bridge conductor. The elements are all. mounted on a base SI of insulating material, which as indicated in Figure 2, may have an upper surface 01' stepped formation consisting of alower step and an upper step It. The odd 85 numbered contact elements are mounted on the lower step ll, the four even numbered elements which have connections leading to the meter being mounted on the upper step. The odd numbered elements on the lower step may each comprise a 4 strip of flat bar stock having a flat mounting portion ll secured to the base 30 and a contacting portion II ansularly disposed with t to the mounting portion ll so as to extend upwardly from the mounting portion and preferably at right angles thereto. Each mounting portion 31 is clamped tightly by a suitable bolt 39 or otherwise, to a. connecting lug 42. As shown in Figure 2, the free end portions 43 of these lugs are bent downwardly along the face ll of the step 35 to prevent turning of the lugs on their bolts. I Thus the projecting portions 42 of lugs of diilerent polarity are prevented from moving nearer to each other than the prescribed minimum spacingdistance. The even numbered contact elements are likewise preferably made of fiat bar stock and are shaped as to have a flat mounting portion 49 and a contacting portion ll angularly disposed relatively thereto, this contacting portion being bent so as to extend downwardly from the upper step 99 toward the lower step 99. The two contacting portions 99 and ll of the opposing elements of each pair are preferably parallel to each other. One or both of these elements is furthermore so shaped as to present a non-flat contacting face toward the other element of the pair. As shown in Figure 6, the contacting portions of the opposing elements may have arcuate cross sections which may be disposed approximately in a common circle. The cross sections of these elements may have other shapes such as that illustrated in Figure 7. As

a result of such structure the connecting plugs are held in an upright position when inserted between the elements of a pair and are prevented from inclining toward each other in such a manner as to reduce the spacing between charged parts of different polarity below the required minimum. Between the elements of each pair is fixed a wall 45 of insulating material such as vulcanized fiber.

Suitable plugs are provided for connecting the elements of the several pairs. As illustrated in Figure 4, a plug may consist of a cylindrical copper rod slotted as at 49 to form a pair of parallel legs 49 adapted to straddle the barrier or wall 45. The convex outer surfaces of the legs 49 are adapted to fit the concaved contact surfaces of the elements 39 and 4|, as indicated in Figure 6, so as to obtain a large interfacial contact for efilcient conduction of current through the connection. Each plug may be provided with an insulating handle member 99 secured to the conducting portion so that the plug may be safely manipulated. If desired the plug may be constructed, as indicated in Figure 5, by bending a piece of flat bar stock into U-shape, the legs 5| of the U-shapedmember being suitably shaped so as to fit against the opposing faces of the contact portions 39 and ll of the elements of a pair. An anchoring pin 52 may be employed to secure the conducting member in the handle ll. Since a bent strip of metal tends to straighten out when heated, it is evident that each of the contacting portions of opposing contact elements will, when heated, tend to move toward the contacting portion of the opposing element. The plug itself also will tend to expand when heated, so that it is evident that a rise of temperature of parts will serve to increase the interfacial pressure between contacting elements and thereby to increase the efficiency of the electrical connection.

The various contact elements may be connected as shown in Figure i. For example, the elements 23 and 25 may be connected respectively to high and low voltage line wires 99 and 9|. The elements 21 and 29 may be connected respectively to low and high voltage load wires 92 and 93. The ground or intermediate voltage wire is shown at 64. Ordinarily plugs are employed to connect the line wires 60 and CI to the meter by connecting contact element 22 with element 23, and element 24 with element 25. The load wires 92 and 63 are ordinarily connected to the meter by plugs connecting element 29 to 21 and element 28 to 29. The high voltage elements 22 and 29 are separated from the low voltage elements 24 and 25 as by a substantial barrier extending across the upper surface of the block. This element may be indented at its ends as at II to provide required minimum surface distance on the insulation between the nearest exposed points of high and low voltage elements. In like manner a similar fixed barrier I! is provided between the low voltage elements 29 and 21 and the high voltage elements 28 and 29. These fixed ban'iers make possible the construction of a test-block occupying a relatively small space but capable of handling currents of comparatively high amperage at the customary voltage.

The contact element 2| is permanently connected to the contact element 29. Likewise the element 20 is connected as by a conductor 19 to the element 29. Thus, by inserting a plug to connect the elements 20 and 2|, the high voltage line wire 60 may be by-passed around the meter to the high voltage load wire 93. The elements 25 and 21 are provided with opposing contact portions separated by a barrier 90 of suitable insulating material. If a plug be inserted to connect these elements, the low voltage line wire 9| is thus by-passed around the meter to the low voltage load wire 92. The four plugs ordinarily employed in the test-block can then be removed without disturbing the load current. A test load may then be connected to the elements 29 and 28. An observation of the reading of the meter will then indicate whether the meter is indicating correctly for the particular test load employed. After the completion of the test, the four customary plugs may be reinserted in the block, thus connecting the load to the line again through the meter. The plugs between the elements 20 and 2| and between the elements 25 and 21 may then be removed so that the full load current thereupon passes through the meter.

The block It may be elevated above the bottom of the box H as by a bridge 98 to which the block may be secured as by a pair of screws 96 extending through the base, insulating plugs 91 being placed over the heads of the screws to prevent short-circuiting.

- It is evident that many modifications and changes can be made in the structure herein described without departing from the spirit or scope of the invention as defined in the follow ing claims.

I claim:

1. A test-block for a meter, comprising an insulating base having a stepped upper surface, and pairs of contact elements on said base, one element of each pair having a mounting portion secured to the higher step and a contact portion bent downwardly from the mounting portion, the opposing elements of each said pair having a mounting portion on the lower step and a contacting portion bent upwardly from the mounting portion to be substantially parallel to the contact portion of the other element of the pair.

2. A test-block for a meter, comprising an insulating base having a stepped upper surface, pairs of contact elements on said base, one element of each pair having a mounting portion secured to the higher step and a contact portion bent downwardly from the mounting portion, the opposing elements of each said pair having a mounting portion on the lower step and a contacting portion bent upwardly from the mounting portion to be substantially parallel to the contact portion of the other element of the pair, an insulating wall between the elements of each pair, and a U-shaped conductor adapted to straddle said wall and engage the elements of a pair.

3. A test-block for a meter, comprising minsulating base, opposing contact elements arranged in pairs on said base, certainof said elements having means freely accessible for theattachment of meter-testing devices, an insulating wall fixed between the opposing elements of each pair, and a U-shaped conductor adapted to straddle said wall and engage and electrically connect the elements of a pair.

4. A test-block for a meter, comprising an insulating base, opposing contact elements arranged in pairs on said base, at least one of each pair of said elements presenting a nonplane contact face to the opposing element of the pair, a wall of insulating material fixed between the elements of each said pair, and a U-shaped conductor adapted to straddle said wall and fit snugly against the elements of a pair.

5. A test-block for a meter, comprising an insulating base, opposing contact elements arranged in pairs on said base, certain of said elements having means freely accessible for the attachment of meter-testing devices, 'eachsaid element having a mounting portion secured to the base and a contact portion angularly disposed with respect thereto, an insulating wall fixed between the elements of each pair, and forked conducting plugs each adapted to straddle said wall and engage the elements of a pair.

6. A test-block for a meter, comprising an insulating base, opposing contact elements arranged in pairs on said base. each said element having a mounting portion secured to said base and a contact portion disposed at an angle to its mounting portion, at least one of said contact portions of each pair of elements'presenting a non-fiat contact face toward the other element of the pair, a wall .of insulating material fixed between the elements of each pair, and a forked conducting plug adapted to straddle said wall and to fit against the opposing contact faces of a pair of said elements.

7. A test-block for a meter, comprising an insulating base having a stepped upper surface with an upper step and a lower step, opposing contact elements arranged in pairs, one element of each pair having a fiat mounting portion secured'to the upper step of said base and a contact portion extending downwardly from the mounting portion, the opposite element of each pair having a mounting portion secured to the lower step of said base anda contact portion extending'upwardly from the mounting portion so as to be substantially parallel to the contact portion of the other element, an insulating wall fixed between the contact portions of each pair of elements, and forked conducting plugs each adapted to straddle said wall and engage the contact elements of a pair.

8. A test-block for a meter, comprising an insulating base, opposing contact elements arranged in pairs on said base, each said element having a fiat mounting portion secured to said base and a contact portion at right angles to the mounting portion. a wall of insulating material between the elements of each pair, and connecting plugs for said pairs of elements, each said plug having a pair of spaced legs adapted to straddle the wall and engage the elements of a pair, said legs having convex cylindrical outer faces, said elements having concave faces adapted for fitted engagement with said legs.

9. A test-block for a meter, comprising a base of insulating material, opposing contact elements arranged in pairs, each said element being formed of flat bar stock bent to provide a fiat mounting portion secured to the base and a contact portion angularly disposed with respect to the mounting portion, said contact portion being shaped so as to present a concave face toward the opposite element of the pair, a wall of insulating material between the elements of each pair, and forked conducting plugs each adapted to straddle said wall and engage with the elementsof a pair, each said plug having-a pair of legs with convex outer surfaces adapted to fit the opposed concave surfaces of the contact elements.

10'. A test-block for a meter, comprising an insulating base, pairs of contact elements mounted side by side on said base, each pair of elements having opposed contact portions arranged to form a hollow area with lateral gaps, and a barrier plate of vulcanized fiber fixed on said base and extending through said gaps to separate an element of each pair from its opposite element.

11. A test-block for a meter, comprising a base of insulating material, one or more pairs of separately disposed electrical conducting members mounted thereon, each of the several members consisting of a strip of metal bent and formed to provide a mounting portion attached to said base and having angularly disposed thereto a formed portion, a pair of said formed portions substantially but not completely enclosing a hollow area, a barrier of insulating material bisecting. said area and closely adjacent to the side edges of said formed portions of the conducting members, and a removable U-shaped conductor straddling said barrier and filling said area to effect electrical connection between said members.

12. A test-block for a meter, comprising an insulating base, a barrier wall of insulating material mounted on said base, a pair of electrical conducting members mounted respectively on opposite sides of said wall, each said member consisting of a mounting portion secured to said base and a formed portion angularly disposed to said mounting portion, each said formed portion being spaced from said wall except for its side edges which substantially abut the wall, whereby each said formed portion encloses with the wall a hollow area, and a U-shaped conductor adapted to straddle said wall and to fill the pair of hollow areas enclosed by a pair of opposed conducting members so as to provide electrical connection between said members.

13. A test-block for a meter, comprising a plurality of pairs of contact elements, certain of said elements having means freely accessible for the attachment of meter-testing devices, and insulat ing means separating said elements and shielding each element from its complementary element and from all elements of polarity different therefrom on said block.

14. A test-block for a meter, comprising a plurality of pairs of contact elements, certain of said elements having means freely accessible for the attachment of meter-testing devices, barrier walls of insulation separating and shielding each element from its complementary element and from all elements of polarity different therefrom on said block, and individual plugs each adapted epeetrto eeidhnnlernllbet'eenpnireoi'oontect elements of dlil'erent Dbllflflfl, and individual pluzsedaptedtoetnddlenldhen'lerwellend connectthecoteryelemenuct npeir.

16. A tut-block for a meizr, comprilng n plurelltyotpairsotoontnctelemenheertainoildd elements hevim meena freely eeeedble for the attachment of meter-testing devices, insuletinz means shielding each eeid element from its oom- ERNET G. JOHANSBON. 

